Ultrasonic mixing method and apparatus therefor



May 14, 1957 D. A. GRIEB 2,791,990

ULTRASONIC MIXING METHOD AND APPARATUS THEREFOR Filed May 21, 1954 2 Shets-Sheet 1 Fig.1 Fig.1.?

IIIIIIIII/ I 1 I I 1 1 I I ll HA5 llTTORNEYS.

//4 INVEN 0R.

May 14, 1957 D. A, GRIEB 2,791,990

ULTRASONIOMEXING METHOD AND APPARATUS THEREFOR Filed May 21, 1954 2 Sheets-Sheet 2 Figdj Fig.1.?

/60 TD Y INVENTOR f f6 I 6 /60 DAN/EL a. 69/58.

BY Y HOB/NEON a KE/SER. 35 1 .15] DES JMDNS I773 flTTORNEYS.

ULTRASONIC MIXING METHOD AND APPARATUS THEREFGR Daniel A. Grieb, Cincinnati, Ohio Application May 21, 1954, Serial No. 431,411

24 Claims. (Cl. 123-52) This invention relates to apparatus for forming intimate mixtures of two or more fluids and, more particularly, to the use of ultrasonic energy for the continuous mixing of fluids passing through the apparatus in a laminar-flow stream. Although my new form of mixing apparatus is particularly suitable for use in the preparation of fuel charges for internal combustion engines, it is not limited to this specific purpose and will be found useful whereever it is necessary to bring two or more fluids into intimate and complete union such as in the mixing of reagents in certain chemical processes, in the preparation of foods which require the emulsification of oils with other liquids, in dissolving solutes which are not readily soluble in the solvent material, etc. I propose to force. the formation of a completely comminuted engine charge, without depending upon volatility, by the direct application of ultrasonic energy so that all of the fuel is thereby treated and so that the amount of fuel so comminuted varies directly with the load requirements as demanded by the accelerator control.

With regard to the application of present invention. to the formation of fuel charges for internal combustion engines, known apparatus and methods for forming such charges have been dependent upon the turbulent flow of the fluid through the mixing apparatus: forobtaining: a mixture of the fuel with the air. This turbulent. flow of the gas. and fuel mixture in the intake manifold of the engine increases the pressure drop through the manifold and reduces the amount of fuel charge which can. be drawn into the engine cylinder on the. intake stroke. thereof. One of the purposes. of my invention istoprovide a fuel intake system in which laminar flow conditions prevail so that the gaseous fuel charge will flow smoothly therethrough and into the cylinders with a minimum of pressure drop within the system.

There are numerous. factors which, must be given consideration in. dealing with the. problem of overcoming turbulence and insuring streamline, flow of the fuel. charge through the intake manifold of the engine. For instance, in the conventional intake manifold, the branches. leading from the header portion of, the manifold to the inlet valves are made uniform in cross-sectional area. When an intake valve closes, the sudden blocking of the forwardly moving fuel charge effects a compression wave-which travels back into the header. This wave creates turbulence in the gases flowing through the header and thereby decreases the quantity of'the'fuel charge: which the engine is able. to draw into the cylindersorrthe. intakestroke. Obviously, theextent of variation in;the-quantity-of-fuel charge drawn into each cylinder is-a functionof the firing sequence of the engine, but none-thei-less, in-. any case, a fluctuation in the power applied to the. crankshaft. results. Furthermore, the. laminar-flow fuel charge. entering; the header must pass through the turbulent gases emitted. by each branch upon the closing of the inlet valves. This completely disrupts the. laminar flow characteristics. of the gases flowing through the header and into the cylinders. This turbulent flow prevents the fuel United States Patent ce 2,791,990 Patented May 14, 1957 charge from entering the cylinders and sluggish and uneven operation of the motor results. Also, this turbulent condition in the manifold is responsible for vapor lock and for the condensation of liquid fuel on the interior walls of the manifold, this being particularly true Where the comminution of the fuel is not complete as in the case of conventional carbureting apparatus. This condensation of the liquid fuel causes slugs thereof to be drawn into the cylinders with resulting oil dilution, pit ting of the valves and fouling of the spark plugs.

In conventional carbureting systems, another cause of turbulence of the fuel charge as it passes through the manifold is due to the interposition of the fuel jet which enters through the wall of the intake conduit and terminates within the center of the Venturi. This has been overcome in my improved mixing apparatus by providing means lying flush with the wall of the conduit for introducing the fuel in a finely divided state into the airstream. I have devised two ways of doing this which will be fully described in a later portion of this specification.

In addition to the elimination of turbulent flow through the intake system of the engine, there is need for finely comminuting all of the fuel and for thoroughly dispersing it with the air or other combustion-supporting gas so as to provide a scientifically prepared and stable engine charge. The greater the comminution, the smaller will be the momentum of the particles and, hence, the less their tendency to coalesce upon impact with obstructions in the manifold such as roughness of the walls, etc. By thus atdmizing the fuel and thoroughly dispersing it with the air, the rate of combustion of the fuel charge in the engine cylinders is increased since the time required for combustion varies directly as the square of the particle diameter. Greater engine speed and increased power and faster acceleration is thereby obtained from the engine. Also, cheaper and less volatile fuels may be utilized by reason of the extent to which the fuel is comminuted and dispersed in the air. In my apparatus, this comminution and dispersion of the liquid fuel in the airstream is brought about by the application of ultrasonic energy to the fuel and air mixture in a novel and highly eflicient manner.

A further factor contributing to the pressure drop in the manifold is the adhesion of the engine charge to the walls of the manifold resulting in smaller fuel charges entering the cylinders during the short interval that the intake valves are open. The phenomenon results in the wetting of the walls of the manifold by the vapor in the fuel charge and causes the resistance to flow through the manifold to be increased. To overcome this condition of wetting of the walls, I propose to coat the interior surfaces of the induction apparatus with a silicone, or other non-wettable material, which will resist any tendency of the fuel particles to coalesce thereon.

Accordingly, it is an object of my invention to provide a fuel intake system for an internal combustion engine inwhichlaminar-fiow conditions will be maintained from the air intake point of the system, through the fuel mixing portion, and finally to the inlet valves of the engine cylinders. This results in a maximum amount of fuel being delivered to all cylinders and provides increased and more uniform power impulses on the crank shaft and a resulting increase in the power output of the engine and faster acceleration response.

Another object of my invention is to provide an intake manifold for an internal combustion engine in which the branches leading ofi the header are designed to dissipate the pressure wave caused by the closing of the inlet valves. Thereby, turbulence in the header or in the branches will be prevented and laminar-flow of the gaseous fuel mixture therethrough will be ensured.

Another object of my invention is to so design the header" and branches of the intake manifold so that the point of termination of each of the branches in the header is so located laterally of the header that each branch will take from the header its share of the fuel charge without interfering with the streamlined flow of the fuel charge to subsequent cylinders.

Another object of my invention is to provide means for introducing the liquid fuel into the airstream in a finely divided state without interfering with the streamline flow of the gases through the induction system.

Another object of my invention is to provide an ultrasonic transducer in the wall of the induction system which is provided with ducts extending from the exterior face of the transducer to the interior face thereof so that the liquid fuel may pass through the transducer and into the airstream in a finely divided or atomized condition. In this form of device, the liquid fuel is highly comminuted as it leaves the inner face of the transducer, and it is further comminuted and dispersed in the combustion air by the ultrasonic vibrations propagated through the airstream.

with the amount of fuel treated so that all of the fuel will be readily borne by the air stream so as to result in efiicient combustion.

Another object of my invention is to provide means for maintaining a pressure head on the liquid fuel during periods when the vehicle is not in use, which head is efiective, upon starting the vehicle, to immediately force the liquid fuel through the fuel introducing element located in the wall of the induction system, and into the air stream.

Another object of my invention is to provide means for varying the pressure applied to the liquid fuel in ac cordance with the power demands of the engine as determined by the position of the engine throttle.

Another object of my invention is to provide means for varying the quantity of the applied ultrasonic energy in accordance with the power output of the engine as determined by the position of the engine throttle.

Another object of my invention is to provide an ultrasonic transducer built up of alternate bars of transducer material and resilient, cushioning material so as to avoid fracturing of the transducer element under the application of high power thereto.

Another object of my invention is to provide the interior surface of the air intake system of an internal combustion engine with a coating of non-wettable ma terial to reduce the tendency of the particles of liquid fuel to adhere to the walls of the manifold.

With these and other objects in view which will becorne apparent from the following description, the inven- .tion includes certain novel features of construction and combinations of parts the essential elements of which are set forth in the appended claims and a preferred form or embodiment of which will hereinafter be described with reference to the drawings which accompany and .form a part of this specification.

in cross-section.

Fig. 2 is a vertical section taken along the line 2-2 of Fig. 1 and including a diagrammatical showing of the foot accelerator and the fuel supply system for the mixin g apparatus.

Fig. 3 is a vertical section taken along theline 3-3 of Fig. 1 to illustrate the staggered disposition of the branch termini across the header.

Fig. 4 is a section taken along the line 44 of Fig. 2. Fig. 5 is a vertical section taken along the line 5-5 of Fig. l to illustrate the construction and mounting of the supersonic transducer.

by depression of the foot pedal 29.

Fig. 6 is a section taken along the line 6-6 of Fig. 5.

Fig. 7 is a schematic view of a modified form of my apparatus.

Fig. 8 is a transverse section taken along the line 88 in Fig. 7.

Fig. 9 shows a variation in the fuel introducing element of Fig. 7 whereby, due to the more limited exposed area of the element to the airstream, greater pressure head or ultrasonic energy can be applied to the fuel to impel it into the airstream.

Fig. 10 is a transverse section through a fabricated type of perimetric transducer unit in which the transducer segments are supported by a resilient damping material to prevent destructive vibration of the transducer under high loads.

Fig. 11 is a diagram of an oscillatorcircuit for driving the ultrasonic transducers.

Fig. 12 is a transverse section taken through a conventional intake manifold and one of its branches leading to a cylinder.

Fig. 13 is a longitudinal section taken through a modified form of transducer unit.

Fig. 14 is a transverse cross-section taken along the line 14-44 of Fig. 13.

Fig. 15 is a transverse section through a modified form of fuel introducing element.

Fig. 16 is a cross-sectional view taken along the line 1616 of Fig. 15.

Figs. 17 and 18 are diagrammatic views illustrating the difference in flow resulting from coating the interior walls of the induction system with a non-wetting agent.

Fig. 19 is an enlarged view of the transducer unit shown in Fig. 1.

As mentioned earlier herein, the invention which forms the subject-matter of this application is particularly suitable for use in connection with the preparation of the fuel charge for internal combustion engines and, accordingly, I have illustrated herein and will hereafter describe this type of application of the invention. It is realized, of course, that the invention is not limited to this particular form of fluid mixing apparatus and that the scope of the invention is to be measured by that of the claims appended hereto.

'20'is the cylinder block of a conventional internal combustion engine in which there are four cylinders which are supplied with a fuel charge through an intake 1nanifold 21 This manifold includes a header portion 22 and four branches 23 which lead from the header to tle intake valves of the cylinders. These branches 23 diverge from the header portion 22 at an angle from 30 to 70. A fuel charge of suitable composition is supplied to the manifold by a throttling and mixing unit 24 which is attached to the manifold. This unit is provided with a gate-type throttling valve 25 (see Fig. 2) which is guided for vertical sliding movement in grooves 26 provided in vthe unit 24. The valve 25 is connected to the piston 27 of a cut-off valve 28 which controls the flow of fuel to the mixing device for a purpose later to be described.

Movement of the valves 25 and 27 is effected by a foot pedal or accelerator 29 which is connected by a link 30 with one end of a pivoted lever 31. The opposite end of this lever is pivotally connected to a rod 32 attached to the piston 27. A compression spring 33 on the lower end of the piston 27 normally urges both valves toward closed position. However, the operator of the vehicle can open the valves to supply increased fuel to the engine Atmospheric air is drawn into the throttling and mixing unit 24 as indicated by the arrow 34 in Fig. 1 to supply oxygen for combustion of the fuel.

After passing through the throttling valve 25, the air moves past a fuel introducing element where the liquid fuel supplying the energy to drive the. engine is mixed with the air. As best shown in Fig. 19, which is an enlargement of the structure shown in Fig. 1, the liquid fuel is dispersed into the airstream by a transducer element which is in the shape of a hollow rectangle and forms a portion of the interior wall of the unit 24. This element may be formed of any suitable material having piezoelectric properties and which can be shaped in the form shown in the drawings. For this purpose, either silicon or any of the well-known ceramic transducer materials which may be given hollow or cylindrical form and rendered piezoelectric by special polarizing treatment during manufacture is suitable. Electrodes are provided on the opposed, fiat faces of the element 40 to which leads 4'1 and 42 are connected for supplying high frequency current to the unit for driving it at a supersonic frequency. To permit free vibration of the transducer unit, it is cushioned in. a ring 43 formed of av resilient material such as. synthetic rubber which will not be detrimentally affected by the fuel supplied to the engine for combustion. The ring 43 is provided with a perimetric feed channel d4 to which gasoline or other suitable fuel is delivered through a pipe 45. The liquid fuel is delivered through the pipe 45 under pressure which is supplied, in this instance, by a gravity feed system as shown in Fig. 2. This system includes a gravity tank 46 to which fuel is delivered from a reservoir 47 by a pump 48. An overflow line 49 returns fuel to the reservoir when the level thereof in the gravity tank reaches the overflow line 49. Connected with the bottom of the gravity tank is a feed pipe 50 which is connected to one port of the cutoff valve 27. The other port of this valve is connected to the pipe 45 so that as long as the valve 27 is open, fuel under a constant pressure head will he delivered to the feed channel 44 (Fig. 19).

It is a novel feature of my invention to feed the fuel into the airstrearn through the transducer element itself so that the fuel will be projected into the airstream in a finely atomized condition. For this purpose, the transducer element may either be made porous so as to provide numerous small ducts through which the fuel may flow from the channel 44 into the air intake conduit or, alternatively, it may be formed with a series of transverse ducts 51 as shown in the drawings. The ducts 51 may either be provided in the transducer element itself, or

they may be formed in the resilient mounting ring 43 at the interface between ring as and element 4%. Hence, when the leads 41 and 42 are connected with a source of high-frequency current, the frequency of this current preferably being in the range of from 50 kilocycles to l megac'ycle, the transducer element will vibrate at ultrasonic frequency to comminute the fuel and project it into the airstreanr flowing through the intake conduit. As the fuel is sprayed into the airstream it will be further agitated and comminuted by the high-frequency Vibrations set up therein by the vibrating inner. face of the element 49. This energy will be directed radially inward and will be effective to comminute the fuel particles and thoroughly disperse them in the intake air. The amount of fuel thus introduced into the airstream will vary directly with the amount of ultrasonic energy applied, to the transducer.

As best shown in Fig. l, the resilient ring 43 in which the transducer element is mounted is clamped between opposed flanges 55 and 56 formed on the ends of conduits 57 and 58 which form a part of the throttling and mixing unit 24. The flanges 55 and 56 are pressed together by a ring-type clamp 59 which is drawn up tight by means of bolts Gil. The features of construction of this, portion of the unit are further illustrated in the sectionalv views, Figs. 5. and 6.

Further agitation of the fuel charge with resulting cornminutionand dispersion of the fuel particles in. the gaseous medium is brought about by additional transducers and 66 which are perimetrically arranged inside the conduit 57 downstream of the transducer element 40. Hence, asthe fuel charge moves through the portion of the conduit 57 occupied by the transducers 65 and 66, it will be subjected to the ultrasonic vibrations produced by the. transducers which are driven from a suitable source of high-frequency electric current which may be the same source as that which drives the transducer element 40. The transducers 65 and 66 may be suitably clamped between. offset shoulders in the conduit through the medium of resilient gaskets 67 which, like the transducers, arev flush with the interior face of the conduit so as to provide a smooth, unbroken surface to the airfuel mixture flowing therethrough.

The generator for producing high-frequency electrical current for driving the transducers 40, 65 and 66 is diagrammatically represented. by the rectangle 68 in Fig. 1-. As shown in Fig. 11, this generator may comprise a Hartley oscillator circuit together with suitable amplifying: stages (not shown) for supplying the power required to drive the transducers at high energy levels.

As shown in Fig. 11, the oscillator circuit comprises a three-element vacuum tube 69 having a filament 7 t) heated by a source. of current 71. A potentiometer 72 connected in the filament circuit provides a voltage drop which serves as a source. of bias for the grid 73 of the tube. 69. The grid is connected to the slider of the potentiometer through a grid leak resistance. 74. The plate 75 of the tube is connected with the positive side of a potential source 76 through. a variable selector tap 81 on an inductor 77. A portion of the oscillatory energy of the plate circuit is fed back to the grid 73 through the. lower end of the inductor which is connected to the grid through a small, blocking condenser 78. The amount of feedback to the grid may be determined by adjustment of the selector tap on the inductor. This control is effected by the knob or dial 79 shown in Fig. 1. The frequency of oscillation may be adjusted by tuning of the variable condenser 80 which is connected in parallel with the inductor to. provide a parallel-resonant circuit. This condenser may be adjusted by means of a dial 81 as shown in Fig. 1 so as to enable the frequency of the ultrasonic vibrations to be adjusted to the point where maximum performance is obtained from the engine. The output of the generator is applied to the transducers through leads 82 and 83 with suitable amplifying stages intervening if necessary. The vacuum tube oscillator heretofore described is by way of example only, it being understood that high-frequency generators employing point contact or junction transistors could be used in place thereof if desired.

As heretofore stated, it is an important feature of my invention to preserve the laminar-flow characteristic of the fuel charge as it passes through the mixing apparatus and into the engine. This increases the efficiency and the power output of the engine due to the reduced pressure drop in the induction system which permits an increased amount of fuel charge to be delivered to each cylinder during the intake stroke thereof. In conventional manifolds for internal combustion engines, as illustrated in Fig. 12, the header portion 9t) of the manifold is connected with the inlet valves by way of branches 91 of uniform cross-sectional area. In this type of manifolding, the pressure surge caused by closing of the inlet valve for each of the cylinders is reflected back into the header and creates a turbulent condition with resultant interference to the streamline flow of the charge to the cylinders. To overcome this condition, I propose to vary the cross-sectional area of the branches as shown in Fig. 1 so that as the pressure surge from the inlet valve proceeds along, the branch toward the header the ever-increasing volume of the branch slows down and dissipates 'vided for conventional carburetion systems.

the inward surge of gas so that it does not reach the header and interfere with the fuel charge passing therethrough. A further novel feature of my manifold is that the termini 92 of the branches are disposed in staggered relation transversely of the header so that, as best shown in Fig. 3, each branch takes its aliquot share of the laminar-flow air-fuel mixture passing into the header. Consequently, laminar flow conditions are maintained along the entire length of the header regardless of the take-offs to the individual cylinders.

The quantity of fuel charge reaching the engine cylinders is controlled by the position of the throttling valve 25 which, as will be noted, is a gate-type valve which 'will admit the intake air into the conduit 58 with a minimum of turbulence. Regardless of the degree of valve opening, each cylinder will be provided with an equal portion of the streamline flow of fuel charge since, as shown in Fig. 2, the width of the valve opening and the width of the conduit and header are equal. This valve, as previously described, is controlled by a foot pedal 29 so as to provide the operator with control of the speed of the engine in a manner similar to that pro- However, as contrasted with the conventional carburetion system employing a butterfly-type throttle valve, the valve 25 will provide a speed response which bears essentially a linear relation with respect to the displacement of the foot pedal. In the conventional system, the speed response is much greater at closed throttle than it is at open throttle. It is also to be noted that there are no obstructions of any sort present in the intake system which would interfere with the flow of air therethrough and that the throttle valve, fuel mixing device, and intake manifold are all proportioned to preserve laminar- 'fiow conditions and to minimize the pressure drop. For

within the branch for the purpose hereinbefore stated.

As shown in Fig. 2, the link 30 is connected at an intermediate point with an arm 93 which is connected with the amplitude control 79 for the high-frequency generator 68 so that when the pedal 29 is depressed to openthe valve 25, the amplitude control will be turned clockwise to increase the amplitude of the current supplied to the transducers 4-0, 65 and 66 (Fig. 1). Therefore, as additional air is admitted to the induction system by opening of the valve 25, additional fuel will be introduced into the air stream by reason of the increased amplitude of vibrations of the transducer 40 which will increase the feed of fuel through this unit and into the 'airstream to maintain the correct air-fuel ratio for most 'efiicient combustion.

When the pedal 29 is released, the spring 33 will close the valves 25 and 27 thereby cutting ofi the flow of air .and also the flow of fuel from the tank 46 to the transducer 40. At the same time, the amplitude control 79 will be adjusted to cut off the supply of high-frequency cur- .rent to the transducer; However, the instant the accelerator pedal 29 is depressed, the valve 27 will open and permit fuel to immediately feed through the lines 50 and 45 to the transducer element which will again ,be energized with high-frequency current and force the formation of a scientifically prepared engine charge by the application of ultrasonic energy.

It is, of course, well known that every rigid body has a point of resonance with respect to mechanical vibrations and this is true of the perimetric transducer elements disclosed herein. The vibratoryrenergy supplied to the transducer may cause it to vibrate at its natural frequency with suflicient amplitude to result in destruction of the transducer. To avoid this occurrence, it is a fea- 8 ture of my invention to provide a built-up or fabricated transducer of perimetric shape such as that shown in Fig. 10. As here shown, the transducer is built up of a plurality of segments formed of a suitable transducer material, and intervening segments 96 formed of a resilient, cushioning substance such as synthetic rubber.

The segments are supported within a cylindrical shell 97 and each transducer segment 95 is provided on its opposite faces with electrodes which are connected in parallel to input leads 98 supplied with suitable highfrequency current. The small segments 95 are much less subject to destruction by resonant vibration than a single, cylindrical transducer element and are free to vibrate individually by virtue of the cushioned mounting afforded by the segments 95 which absorb energy from the system and dampen the vibration of the segments. Hence, a very durable and effective transducer is provided.

A modification of my invention is shown in Fig. 7 in which fuel under pressure is supplied to a fuel introducing element which is made of porous, rigid material so as to permit the fuel to be forced therethrough and into the airstream passing through the intake conduit. The fuel introducing element is numbered 190 in Fig. 7 and, like the transducers 40, 65 and 66 in Fig. 1, is arranged in perimetric relation with respect to the intake conduit 101. Air or other suitable combustion supporting gas enters the conduit in the direction indicated by arrow 102 through which it flows with a minimum of turbulence. Liquid fuel is introduced into the airstream through the element in a finely divided state after which the combined fuel and air mixture is subjected to ultrasonic vibrations by means of suitable transducers 103 and 104. These transducers are similar to transducers 65 and 66 heretofore mentioned in connection with the Fig. 1 form of my invention, and are connected with the output of a high-frequency generator 105 having an amplitude control dial 196 and a frequency control dial 107. In this form of the invention, a cut-off valve 108 having a piston 109 is provided for controlling the flow of fuel under pressure through a pipe 110 to a feed channel surrounding the exterior face of the element 100. The piston 199 of the valve 168 is connected with a gate-type throttli'ng valve (not shown) like the valve 25 which is interposed in the intake conduit 191 ahead of the element 100 and serves to control the amount of air flowing therethrough. 'The positions of the throttling valve and cutoif valve 108 are, like the corresponding valves 25 and 28, controlled by a foot pedal 111. This foot pedal also controls, through an arm 112, the frequency control 197 of the generator 105 so as to increase the frequency of the current and thereby supply additional energy to the transducers 103 and 1134 for increased amounts of fuel and air passing through the intake conduit. As shown in the drawing, the arm 112 is extended beyond the frequency control shaft where it is pivotally connected to a rod 113 attached to the piston 199 for the purpose of controlling the throttling and cut-off valves.

The pressure of the fuel supplied to the element 100 is likewise controlled by the foot pedal 111. To this end, fuel from a reservoir 114 is delivered by a pump 115 through a check valve 116 to an accumulator 117. Fuel under pressure from the accumulator is delivered through a pipe 113 to one port of the valve 198, the other port of which is connected by pipe 110 with the fuel intro ducing element 1%. Connected between the discharge side of the pump 115 and the fuel reservoir 114 is a throttling valve 119. This valve is controlled by an arm which is connected with the foot pedal 111 so that as the pedal is depressed, closing of the valve 119 is effected to thereby reduce the flow of fuel back into the reservoir from the pump 115 and thus increase the pressure of the fuel delivered to the element 100. Hence, as the foot pedal 111 is depressed, increased air will be permitted to flow into the intake conduit, an increased pressure head will be applied to the fuel flowing to the element 1G0, and the frequency of the oscillatory current Q supplied to the transducersltlfa and 1&4 will be increased so as toincrease the amount and effectiveness of theultrasonic energy supplied for agitating and dispersing the liquid fllfll into. the airstream. By reason of the porous nature of the element 1%, the liquid fuel will be sprayed therefrom. in a finely divided state so as to prepare the fuel charge for further disintegration and dispersion by the transducers 103 and 104. A variation. in the form of the-element 1590 is shown in Fig. 9, wherein a plurality of cylindrical, plug-shaped porous elements 126 are. provided in the Walls of intake conduit 127 and supplied withfuelunder pressure through pipes 125.

A modification of the invention is shown in Figs. 13 and 14, wherein a pair of transducers 130 and 131 are provided on opposite sides of a rectangular air intake conduit 132 which preferably is the same size as the eutrance tothe headerv portion of the manifold. These elementS are, provided with electrodes 133 and 134 to which higlnfrequency current may be applied by leads 135 and 13,6. Thetransducers may optionally be constructed of porous material soas to provide ducts for thepassage of liquid fuel'therethrough and into the air stream, or they maybe constructed with a number of small, transverse ducts 137 as indicated in Figs. 13 and 14. Fuel under pressureissupplied .to the exterior faces of the transducers by means of pipes 138 which deliver fuel into the feed cavity 139 provided in the resilient mountingbushing 14G behind each transducer. The liquid fuel delivered to the transducers through the pipes 138 will thereby be highly comminutedasrit is, sprayed from the transducers into the airstieam. Likewise, the resulting air-fuel mixture will beviolently agitated with resulting commiaution and dispersion of the fuelparticles in the'air by the ultrasonic vibrations generatedinthe intake conduit between the transducers 130 and'131.

A furtherform of transducer-type fuel introducing element is shown in Figs. and 16 in which the element is in the form of .a cylindrical plug, it being indicated by reference numeral 150 in these figures. This element is mounted in a bushing 151 formed of resilient material so as to permit free vibration of the element 150 under the. influence of high-frequency electric current applied thereto, by leads 152 and. 153 which are connectedto electrodes formed on opposite sides of the element as shown in Fig. 16. Fuel under pressure is delivered to the outer end of the element 150 by means of a fuel'pipe 154 and the element 15% may be formed either. ofa porous type of transducer material to permit the fueljto pass therethrough and into the air intake conduit 155 or, alternatively, it may be providedwith small ducts 156 for permitting fuel to be deliveredin a fihely comminuted state of the air passing through the conduit.

A further feature ofmy invention resides in the provision of a non-wetting agent on the interior surface of the intake manifold and conduit portions of the throttling and mixing unit 24 so as to prevent wetting of the interior walls of the manifold by the fuel charge. passing therethrough. In this way, the frictional resistance of the manifold to the passage of the gaseous fuelcharge therethrough is considerably reduced, thereby diminishing the pressure drop in the manifold and increasing the efiiciency and power output of the engine. This is brought out in Figs. 17 and 18 which are diagrammatic representations of the conditions of flow of the fuel charge through the manifold. In Fig. 17, velocity vector X-is a maximum at the axis because here it is farthest away from the interior surface of the conduit wherethe velocity is zero due to the wetting of the surface by the fuel charge. As this adhesive force is overcome by the suction produced by the engine within the manifold, the velocity vector increases. However, the dissipation in this manner of the suction created by the pistons prevents lthe maximum fuel charge from entering the cylinders andprevents maximum power output from the engine.

In. Fig. 18. is shown a cross sectional view through a conduit which has been. treated with a n-weing agent in order that the charge may not wet the conduit surface. A suitable agent for. this purpose is siloxane, a member of the silicone. family, which is well known for its nonwetting properties. The species of siloxane' known as dimethyl polysiloxane is especially suited to the type of application here involved although it is to be realized that certain of the other derivatives of siloxane may prove satisfactory for this purpose. This agent may be dissolved in a solvent and applied in the form of a liquid coating 160 to the interior surface of the conduit. The coating may be air. dried and. then baked to provide a surface which will. resist adhesion of the fuel particles in the engine charge on the walls of. the conduit; As shown in Fig. 18, the velocity vector Y is constant across practically the entire conduit there being only a small amount of drag present in the immediate vicinity of the walls. Hence, the amount offuel charge flowing through the conduit for a. given amount of suction produced by the engine is greatly increased over that for conduits not so treated.

While I hae described my invention in connection with several'possible: forms or embodiments thereof and have used certain specific terms and language herein, it is to be understood thatthe present disclosure is illustrative rather than restrictive and that changes and modiflcationsmay be resorted to without departing from the spirit orv scope of the claims which follow.

Having thus described my invention, what I claim as new and usefuLand desire to secure by United States Letters Patent, is:

1. Apparatus for continuously and intimately mixing one fluid with a laminar-flow stream of another fluid whilemaintaining the laminar-flow characteristics of the stream comprising a conduit of uniform and constant cross-sectional areav for containing the laminar-flow stream of fluid, a fluid transmitting element situated within said conduit and forming an unbroken portion of the peripheral wall of corresponding uniform and constant cross-sectional area for introducing said one fluid into said stream in a finely divided state, means for delivering said one fluid under pressure to the exterior surface of said element for transmissionthrough said element into said conduit, and perimetric means for applying ultrasonic energy to the fluids in said conduit in the vicinity of said element so as to violently agitate and intermix the particles thereof while maintaining the laminar-flow properties of the stream.

2. The apparatus of .'claim 1 in whichsaid element is a transducer, and means for driving said transducer at an ultrasonic frequency to cause the fluid transmitted thereby to be introduced into the streamin a highly comminuted state.

3. The apparatus of claim 2 wherein said transducer is provided with'a plurality of ducts connecting the exterior andinterior faces thereof.

4. The apparatus of claim 2 wherein said transducer is comprised of .a porous, ceramic material.

5. The apparatus of claiml wherein said element is comprised of a porous, rigid material.

6. The apparatus of claim 1 including a linear throttle valve in said conduit on the upstream side of said element, meansfor varying the amount of ultrasonic energy applied to the fluids in said conduit, and means for simultaneously'adjusting said throttle valve and said varying means to coordinate the amount of fluid flowing through said conduit with theamount of ultrasonic energy applied thereto.

7. Apparatus for continuously and intimately mixing one fluid with. a laminar-flow stream of another while maintaining the laminar-flow characteristics of. the stream, comprising a conduit for containing the laminar-flow stream of fluid, a perimetric transducer in said conduit disposed with its inner face flush with the interior wall 11 of said conduit, a plurality of ducts communicatively connecting the outer face of said transducer with the inner face thereof, and means for delivering said one fluid to the outer face of said transducer, said means including a gravity tank located at a higher elevation than said transducer.

8. Apparatus for continuously and intimately mixing one fluid with a laminar-flow stream of another fluid while maintaining the laminar-flow characteristics of the stream, comprising a conduit for containing the laminarflow stream of fluid, a perimetric element in said conduit having inner and outer faces and disposed with its inner face flush with the interior Wall of said conduit, said element being constructed of a porous, rigid material capable of transmitting fluid from its outer face to its inner face, and a pump for delivering said one fluid under pressure to the outer face of said element for transmission through said element into said conduit.

9. A fuel intake system for an internal combustion engine wherein a liquid fuel is finely comminuted and dispersed in a laminar-flow stream of a combustion-supporting gas comprising an intake conduit of uniform and constant cross-sectional area, a liquid transmitting element situated within said conduit in perimetric relation thereto so as to form an unbroken portion of the interior wall of corresponding uniform and constant cross-sectional area, means for delivering the liquid fuel under pressure to the exterior face of said element and cause it to be forced therethrough and into the stream of gas, rectangular means for applying ultrasonic energy 'to the fuel-gas mixture in the conduit in the vicinity of said element to comminute the fuel and disperse it in the gas while maintaining the laminar-flow characteristics of the stream, and a gate valve located in said conduit upstream of said element for controlling the flow of gas through the conduit.

10. The system of claim 9 wherein said conduit includes a header with branches diverging therefrom to transmit the gaseous fuel charge to the inlet ports of the engine, said branches each tapering from a section of large crosssectional area at the header end to a section of small cross-sectional area at the port end to dissipate therein pressure surges occurring at the inlet ports of the engine.

11. The system of claim 10 wherein said branches diverge from said header at an angle of from 30 to 70.

12. The system of claim 10 wherein the termini of the branches in the header are spaced progressively across the header so that each branch takes out its proportionate share of the gaseous fuel charge passing in a laminar-flow stream through the header while maintaining the laminarflow characteristics within itself.

13. The system of claim 9 in which said element is an electro-mechanical transducer.

14. The apparatus of claim 2 wherein said transducer is formed of silicon.

15. The apparatus of claim 2 wherein said perimetric means is rectangular and transducer is of rectangular shape so as to provide a uniform ultrasonic energy field extending transversely across said conduit.

16. Apparatus for continuously and intimately mixing one fluid with a laminar-flow stream of another fluid while maintaining the laminar-flow characteristics of the stream comprising a conduit of uniform and constant cross-sectional area for containing the laminar-flow stream of fluid, ta fluid transmitting element situated within said conduit and forming an unbroken portion of the peripheral wall thereof for introducing said one fluid into said stream in a finely divided state, means for delivering said one fluid under pressure to the exterior surface of said element for transmission through said element into said conduit, and means for applying ultrasonic ener to the fluids in said conduit in the vicinity of said element so as to violently agitate and intermix the particles thereof while maintaining the laminar-flow properties of the stream, said applying means including a perimetric transducer lying flush with the interior wall of said conduit on the down-stream side of said element.

17. Apparatus for continuously and intimately mixing one fluid with a laminar-flow stream of another fluid while maintaining the laminar-flow characteristics of the stream comprising a conduit of uniform and constant cross-sectional area for containing the laminar-flow stream of fluid, a fluid transmitting element situated within said conduit and forming an unbroken portion of the peripheral wall thereof for introducing said one fluid into said stream in a finely divided state, means for de livering said one fluid under pressure to the exterior surface of said element for transmission through said element into said conduit, means for applying ultrasonic energy to the fluids in said conduit in the vicinity of said element so as to violently agitate and intermix the particles thereof while maintaining the laminar-flow properties of the stream, means for varying the amount of ultrasonic energy applied to the fluids in said conduit, means for varying the pressure head on said one fluid, and positional means for simultaneously adjusting both of said varying means to provide an amount of energy commensurate with the amount of one fluid introduced into said conduit.

18. The apparatus of claim 17 wherein said delivering means includes an accumulator, and a valve controlled by said adjusting means for blocking the flow of said one fluid from said accumulator to said element in a prcdetermined position of said adjusting means.

l9. Apparatus for continuously and intimately mixing one fluid with a laminar-flow stream of another fluid while maintaining the laminar-flow characteristics of the stream comprising a conduit of uniform and constant cross-sectional area for containing the laminar-flow stream of fluid, a fluid transmitting element situated within said conduit and forming an unbroken portion of the peripheral wall thereof for introducing said one fluid into said stream in a finely divided state, means for delivering said one fluid under pressure to the exterior surface of said element for transmission through said element into said conduit, means for applying ultrasonic energy to the fluids in said conduit in the vicinity of said element so as to violently agitate and intermix the particles thereof while maintaining the laminar-flow properties of the stream, means for varying the amount of ultrasonic energy applied to the fluids in said conduit. means for adjusting said varying means, and a valve controlled by said adjusting means for blocldng the flow of fluid from said delivering means to said element in a predetermined position of said adjusting means.

20. Apparatus for continuously and intimately mixing one fluid with a laminar-flow stream of another fluid while maintaining the laminar-flow characteristics of the stream comprising a conduit of uniform and constant cross-sectional area for containing the laminar-flow stream of fluid, an electro-mechanical transducer situated within said conduit and forming an unbroken portion of the peripheral wall thereof for introducing said one fluid into said stream in a finely divided state, a resilient mount engaging with the side faces of said transducer for supporting it in the wall of said conduit, a plurality of transversely extending ducts provided at the interface of said mount and said transducer, said ducts forming discrete channels for interconnecting the exterior and interior faces of said transducer, means for delivering said one fluid under pressure to the exterior sunace of said transducer for transmission therethrough into said conduit and means for applying ultrasonic energy to the fluids in said conduit in the vicinity of the transducer so as to violently agitate and intermix the particles thereof while maintaining the laminar-flow properties of the stream.

21. The apparatus of claim 20 wherein said ducts are provided in the side faces of said transducer.

22. The apparatus of claim 21 wherein said ducts are formed in the side faces of said resilient mount.

23. Apparatus for continuously and intimately mixing one fluid with a laminar-flow stream of another fluid while maintaining the laminar-flow characteristics of the stream comprising a conduit of uniform and constant cross-sectional area for containing the laminar-flow stream of fluid, a fluid transmitting element situated within said conduit and forming an unbroken portion of the peripheral wall thereof for introducing said one fluid into said stream in a finely divided state, means for delivering said one fluid under pressure to the exterior surface of said element for transmission through said element into said conduit, and means for applying ultrasonic energy to the fluids in said conduit in the vicinity of said element so as to violently agitate and intermix the particles thereof while maintaining the laminar-flow properties of the stream, said ultrasonic energy applying means including a built-up unit having alternating segments of transducer material and resilient dampening material.

24. A fuel intake system for an internal combustion engine wherein a liquid fuel is finely comminuted and dispersed in. a laminar flow stream of a combustion-supporting gas comprising an intake manifold to which is connected an intake conduit of uniform and constant crosssectional area, said manifold and conduit being coated on their interior surfaces With a non-wetting substance, a liquid transmitting element situated with said conduit in perimetric relation thereto so as to form an unbroken portion of the interior wall thereof, means for delivering the liquid fuel under pressure to the exterior face of said element and cause it to be forced therethrough and into the stream of gas, means for applying ultrasonic energy to the fuel-gas mixture in the conduit in the vicinity of said element to comminute the fuel and disperse it in the gas while maintaining the laminar-flow characteristics of the stream, and a gate valve located in said conduit upstream of said element for controlling the flow of gas through the conduit.

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